I checked the site, on which I found this code. Creator of this code says:
BTW the new code I made, allow you to load more music:
File Patch Code v3.5.1: [Phantom Wings, ported by Deathwolf] [and so on...]
His words mean, that we can load custom music with this code. Am I doing something wrong, or is my Wii/Gecko/anything else not designed for the code?